Telephonic transmitter



(No Model.)

2 Sheets-Sheet 1. O. G. HUGHES.

TELEPHONE TRANSMITTER.

Patented July 9, 1895.

fl v, 9 .m 4 3:11: J 3- w :55! llnnnlviiljw I w No Model.) 2 SheetsSheet 2 O; O. HUGHES.

TELEPHONE TRANSMITTER. No. 542,444; Patented July 9, 1895.

wwmaom EErcE ATENT c1-IARLES o. HUGHES, or BALTIMORE, MARYLAND.

TELEPHONIC TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 542,444, dated July 9, 1895. Application filed September 12, 1894. Serial No. 522,832. (No model.)

specific class of transmitters, multiple electrode, the object of my inventionbcing to provide such construction as will produce a transmitter which will have the utmost delicacy of transmission, which shall not be liable .to buzzing due to abrasion of the electrodes, which shall be compact in form, and shallbe easy of manufacture, the said transmitter to be specially applicable to house Systoms and other short lines involving no induced currents, although it is found to operate equally well under all conditions.

With these objects in view, my invention consists in providing a suitable casing inclosing a preferably annular chamber, at one side ofjwhich and opening into said chamber is arranged the usual funnel, adjacent to whose inner opening is arranged a diaphragm having a button of peculiar form and of high electrical resistance secured thereto and diametrically opposite to a similar button attached to a second diaphragm which is Secured in place on the opposite side of the easingby means of a suitable bridge and acts to form a closure for the other end of the said annular chamber. Placed loosely between these buttons is an electrode, preferably of similar material and varying in form in accordance with that of its adjacent buttons. Suitable connections are made from the buttons to the line and battery or battery and primary winding of ind notion-coil, as the case may be.

Referring now to the drawings forming a part of this specification and inwhich like symbols of reference indicate similar parts in the several views, Figure 1 is a vertical section of the preferred form of my invention. Fig. 2 is a modification showing a reversal of the forms of the electrodes. Fig. 3 is a vertical section of a transmitter, showing the employment of a double cone in place of the ball in Fig. 1. ing a reversal in form of the electrodes shown in Fig. 8.

In constructing a transmitter in accordance with my invention, I form a preferably cylindrical casing 6, although it is evident that it may be of any desired form, inclosing a longitudinal chamber 7. The periphery of the casing 6 may be provided with screw-threads 8 atone edge thereof to receive the flange 9 of the usual conical mouthpiece 9. The outer face of the casing 6-that is, the face adjacent to the mouthpiecehas a countersunk portion resulting in a shoulder 10, betweenwhich and a correspondinglyformed shoulder 11 on the flange 9 is held a diaphragm 12, of any suitable material, and at the center of which and on the inner surface is secured a button 13, whose free end is provided with a conical depression 14., the extent of whose angle is preferably 90 degrees.

The rear face of the casing 6 is countersunk in a manner similar to that of the front face, resulting in an annular shoulder 15, against which is'clamped a second diaphragm 16 by means of an elastic bridge 17, arranged diametrically of the diaphragm. This bridge may be held in place by screws 17, as shown, or in any other manner whereby it may be adjusted when desired. Secured to the inner face of the diaphragm 16 and at the center thereof is a second button 18, similar in construction to 13, and arranged with its conical recess against that of the former, whereby a double conical chamber is formed, in which is held a sphere 19, whose diameter is slightly less than the perpendicular distance between opposite points in the surfaces of the depressions of thebuttons. The buttons 13 and 18 may be secured to their respective diaphragms in any desired manner, such as by means of bolts, as shown, in which latter case the bolt 20 of the button 18 is passed entirely through the bridge 17. Suitable electrical connections areattached to the buttons 13 and 18, or in the event of iron diaphragms being used connection may be made with any portions of said diaphragms, as will be readily seen.

Fig. 4 is a similar view show- IOC tical in form and arrangement with those of the elements shown in Fig.1,with the exception of the free electrode30, which inthe latter instance isin'the 'formof a double cone instead of a sphere.

In Fig. 4 I have shown a transposition in the form of the electrodes shown in-Fig.l3,

thetwo buttons 40'and 41 having conical-extremities holding in'su'spension a cylinder 42 provided withconical depressions inits'ends torec'eive the said conical extremities.

. It will be noted that in each application of my invention as set forth in thedrawin'gs herewith the free electrode bears'u'pon' sur-' faces less than tangent'that' is, the surfaces are curved wherebya variation in the extent of contact is secured in accordance with the: vibration of the'receiving-diaphragm;andin the case of the form ShO\VDll'1F'lg.'1 as theelec trodes 13 and'ls'approach each 'ot'herthe lineof conductivity through theelectrod'e 19' approaches the diameter,- and *at'-the-sarne"- time the'points'of-contact betweenthe elec trode 19 and the electrodes 13 and lStend to form an ever-increasing circle approaching the great circle;

It'will thus be seen that I have provideda Very simple and cheap.construction;having but few parts, readily adjustable, and the parts of which may be easily replaced." Moreover, the free electrodein each 'construction 'is' so formed and is so'arranged with respect to'its l abutting electrodes as to prevent sliding and other objectionable motions and theresultant buzzing due to abrasion and loosemotion of the elements. 7

I do not limit myselfto any'particula'r material in the manufacture-of my invention, as

it will be-readily'understood that I may. em"- ploy any'resilient material for the diaphragms and may use any substance for the electrodes, K a

it being preferable, of course, toemploy a material for the latter which possesses a high coeffi'cient of resistance-t0 electricity;

Having now described my invention and the means for carrying it into effect, what I claim is 1. In a telephone transmitter, an electrode having a cavity whose sections on planes perpendicular to the direction of motion are arcs ofcircles of gradually varying radii, and the co-operating electrode having an exterior surface whose sections in the same planes are also arcs 'of cir'cle's'of varying radii, the radii of the arcs of normal contact of the electrodes differingin value. v

' 2. Atele plione transmitter, comprising a diaphragmadapted to receive sound waves, an electrode secured thereto, a second dia phragm havinga similar electrode secured thereto',-each of said electrodes 'having'a cavitywhose sections in'planes perpendicular to the directio'nof mot-i'o'n'are arcs of circles of graduallynvaryingradii, and a free'electrode heldin'suspension'bytheaforesaid'electrodes, and havingan exteriorsurface whose sections in planes perpendicularto the directior'rof mo-' tion are-alsoarcs of-circles ofvarying radii, the radii ofthe'arc's of'normal' contact ofthe electrodes differingsin value:

SwIn-atelephone transmitter; the combination of'a diaphragmad'apted to receive soundwaves, an electrodesecured thereto and hav ing a reentrancconi cal' surface, a second diaphragm-provided with an electrode secured theretohavinga reentrant conical surface, a freeelect'rodearranged tomove'over saidsnrfacesin accordance-withsound-waves to vary the area-of themutual contact of the surfaces of theelectrodes;

4c. In'a'telephone transmitter, the combina tion witha'diaphragm'provided withan electrod'e'securedt-hereto'having a reentrant coni cal surface, a second 'electr0d'eprovided with asuitable support, and having also a reentrant conical'snrlace,'and a free'electrode in contact witlr-said surfaces and adapted to move thereover'to vary-thearea of 'contact in accordance with sound-waves acting on thesaid diaphragm.

In testimony:w-hereof=l afiti'inny signature in presence of two witnesses; I

. CHARLES (l. HUGHES; VVitnes'sesr WM. E. DELLA, Tnos; M: DOBBIN.

IOC 

